Alc/effects/compressor.c

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2013 by Anis A. Hireche
   4  * This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  *  License along with this library; if not, write to the
  16  *  Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  * Or go to http://www.gnu.org/copyleft/lgpl.html
  19  */
  20
  21 #include <stdlib.h>
  22
  23 #include "config.h"
  24 #include "alError.h"
  25 #include "alMain.h"
  26 #include "alAuxEffectSlot.h"
  27 #include "alu.h"
  28
  29
  30 typedef struct ALcompressorState {
  31     DERIVE_FROM_TYPE(ALeffectState);
  32
  33     /* Effect gains for each channel */
  34     ALfloat Gain[MAX_EFFECT_CHANNELS][MAX_OUTPUT_CHANNELS];
  35
  36     /* Effect parameters */
  37     ALboolean Enabled;
  38     ALfloat AttackRate;
  39     ALfloat ReleaseRate;
  40     ALfloat GainCtrl;
  41 } ALcompressorState;
  42
  43 static ALvoid ALcompressorState_Destruct(ALcompressorState *UNUSED(state))
  44 {
  45 }
  46
  47 static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
  48 {
  49     const ALfloat attackTime = device->Frequency * 0.2f; /* 200ms Attack */
  50     const ALfloat releaseTime = device->Frequency * 0.4f; /* 400ms Release */
  51
  52     state->AttackRate = 1.0f / attackTime;
  53     state->ReleaseRate = 1.0f / releaseTime;
  54
  55     return AL_TRUE;
  56 }
  57
  58 static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCdevice *device, const ALeffectslot *slot)
  59 {
  60     aluMatrixf matrix;
  61     ALfloat scale;
  62     ALuint i;
  63
  64     state->Enabled = slot->EffectProps.Compressor.OnOff;
  65
  66     scale = device->Dry.AmbiScale;
  67     aluMatrixfSet(&matrix,
  68         1.0f,  0.0f,  0.0f,  0.0f,
  69         0.0f, scale,  0.0f,  0.0f,
  70         0.0f,  0.0f, scale,  0.0f,
  71         0.0f,  0.0f,  0.0f, scale
  72     );
  73     for(i = 0;i < 4;i++)
  74         ComputeFirstOrderGains(device->Dry.AmbiCoeffs, device->Dry.NumChannels,
  75                                matrix.m[i], slot->Gain, state->Gain[i]);
  76 }
  77
  78 static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels)
  79 {
  80     ALuint i, j, k;
  81     ALuint base;
  82
  83     for(base = 0;base < SamplesToDo;)
  84     {
  85         ALfloat temps[64][4];
  86         ALuint td = minu(64, SamplesToDo-base);
  87
  88         /* Load samples into the temp buffer first. */
  89         for(j = 0;j < 4;j++)
  90         {
  91             for(i = 0;i < td;i++)
  92                 temps[i][j] = SamplesIn[j][i+base];
  93         }
  94
  95         if(state->Enabled)
  96         {
  97             ALfloat gain = state->GainCtrl;
  98             ALfloat output, amplitude;
  99
 100             for(i = 0;i < td;i++)
 101             {
 102                 /* Roughly calculate the maximum amplitude from the 4-channel
 103                  * signal, and attack or release the gain control to reach it.
 104                  */
 105                 amplitude = fabsf(temps[i][0]);
 106                 amplitude = maxf(amplitude + fabsf(temps[i][1]),
 107                                  maxf(amplitude + fabsf(temps[i][2]),
 108                                       amplitude + fabsf(temps[i][3])));
 109                 if(amplitude > gain)
 110                     gain = minf(gain+state->AttackRate, amplitude);
 111                 else if(amplitude < gain)
 112                     gain = maxf(gain-state->ReleaseRate, amplitude);
 113
 114                 /* Apply the inverse of the gain control to normalize/compress
 115                  * the volume. */
 116                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 117                 for(j = 0;j < 4;j++)
 118                     temps[i][j] *= output;
 119             }
 120
 121             state->GainCtrl = gain;
 122         }
 123         else
 124         {
 125             ALfloat gain = state->GainCtrl;
 126             ALfloat output, amplitude;
 127
 128             for(i = 0;i < td;i++)
 129             {
 130                 /* Same as above, except the amplitude is forced to 1. This
 131                  * helps ensure smooth gain changes when the compressor is
 132                  * turned on and off.
 133                  */
 134                 amplitude = 1.0f;
 135                 if(amplitude > gain)
 136                     gain = minf(gain+state->AttackRate, amplitude);
 137                 else if(amplitude < gain)
 138                     gain = maxf(gain-state->ReleaseRate, amplitude);
 139
 140                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 141                 for(j = 0;j < 4;j++)
 142                     temps[i][j] *= output;
 143             }
 144
 145             state->GainCtrl = gain;
 146         }
 147
 148         /* Now mix to the output. */
 149         for(j = 0;j < 4;j++)
 150         {
 151             for(k = 0;k < NumChannels;k++)
 152             {
 153                 ALfloat gain = state->Gain[j][k];
 154                 if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
 155                     continue;
 156
 157                 for(i = 0;i < td;i++)
 158                     SamplesOut[k][base+i] += gain * temps[i][j];
 159             }
 160         }
 161
 162         base += td;
 163     }
 164 }
 165
 166 DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
 167
 168 DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
 169
 170
 171 typedef struct ALcompressorStateFactory {
 172     DERIVE_FROM_TYPE(ALeffectStateFactory);
 173 } ALcompressorStateFactory;
 174
 175 static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
 176 {
 177     ALcompressorState *state;
 178
 179     state = ALcompressorState_New(sizeof(*state));
 180     if(!state) return NULL;
 181     SET_VTABLE2(ALcompressorState, ALeffectState, state);
 182
 183     state->Enabled = AL_TRUE;
 184     state->AttackRate = 0.0f;
 185     state->ReleaseRate = 0.0f;
 186     state->GainCtrl = 1.0f;
 187
 188     return STATIC_CAST(ALeffectState, state);
 189 }
 190
 191 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
 192
 193 ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
 194 {
 195     static ALcompressorStateFactory CompressorFactory = { { GET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory) } };
 196
 197     return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
 198 }
 199
 200
 201 void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
 202 {
 203     ALeffectProps *props = &effect->Props;
 204     switch(param)
 205     {
 206         case AL_COMPRESSOR_ONOFF:
 207             if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
 208                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 209             props->Compressor.OnOff = val;
 210             break;
 211
 212     default:
 213         SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 214     }
 215 }
 216 void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 217 {
 218     ALcompressor_setParami(effect, context, param, vals[0]);
 219 }
 220 void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat UNUSED(val))
 221 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 222 void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 223 {
 224     ALcompressor_setParamf(effect, context, param, vals[0]);
 225 }
 226
 227 void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
 228 {
 229     const ALeffectProps *props = &effect->Props;
 230     switch(param)
 231     {
 232         case AL_COMPRESSOR_ONOFF:
 233             *val = props->Compressor.OnOff;
 234             break;
 235         default:
 236             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 237     }
 238 }
 239 void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 240 {
 241     ALcompressor_getParami(effect, context, param, vals);
 242 }
 243 void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat *UNUSED(val))
 244 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 245 void ALcompressor_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 246 {
 247     ALcompressor_getParamf(effect, context, param, vals);
 248 }
 249
 250 DEFINE_ALEFFECT_VTABLE(ALcompressor);